The present invention pertains to gauges normally installed on the side of an industrial storage tank for liquids to provide a visual indication of the liquid level in the storage tank.
Generally such gauges, in current use, utilize a length of glass tubing, or the like, in communication at its top and bottom ends with shut off valves in place on a tank wall. With the valves open, liquid level in the glass tank corresponds to the level of tank contents.
The glass tube is usually several inches in length, which renders the gauge susceptible to breakage upon being accidentally struck by other equipment or by forceful streams of water or steam during a cleaning operation. Attempts to shield the glass tubing include metal rods laterally offset from the gauge. Such rods only partially shield the tube to avoid obscuring same.
A common problem with such gauges results from reliance on packing at the tube ends at the valve connection. If the packing is over compressed during tightening of the gauge fittings the tube end may shatter while if not adequately tightened or compressed, the packing may leak.
Replacement of damaged sight gauges is a time consuming and costly operation and in some installations may require emptying of the associated storage tank or at least lowering of tank level. Loss of tank fluid from a broken liquid level gauge can result in damage to a plant and, depending on the liquid, costly environmental consequences from the resulting spill.
The present invention is embodied in a gauge for installation on a liquid storage tank with the gauge having a translucent tube assembly with metallic end segments.
The end segments are not susceptible to damage from accidental over-tightening and hence attachment to an associated valve may be in a tight manner obviating leakage.
The end segments of the tube assembly are secured to the translucent glass tube during manufacture of the tube assembly. The glass or translucent component of the present gauge is protected by a housing able to withstand random impacts from equipment such as that used in industrial sites.
Important objectives of the present gauge include the provision of a translucent sight gauge having a tube assembly with non-breakable end segments capable of withstanding substantial compression forces to the extent packing to seal the tube ends may be dispensed with; the provision of a gauge which may be several feet in length and fully protected by a housing along its length; the provision of a liquid level gauge allowing replacement of the translucent tube assembly by dispensing with packing about the tube ends; the provision of a liquid level gauge having a metal housing in place about a translucent tube assembly with the housing having couplings at each end engaging metal end segments of the translucent tube assembly in a secure packing free manner without risk of damage to the tube assembly and without reliance on packing.